Philip Roth chats with RB Kitaj as he sits in chair next to the artist's 1985 drawing of the author. Photograph: Ian Cook/Getty Images

Ronald Kitaj, who died on Sunday, was a restless artist. He moved from Ohio to London to, finally, Los Angeles. He darted between idioms. And he was always hungry for ideas to chew over, to quote, to dispute.

In all this dizzying motion, critics sometimes overlooked what remained constant: his sensuous portraits and a sincere engagement with history. Sometimes this appeared to be mere citation: paintings are named after both the American journalist Walter Lippman and the German philosopher Walter Benjamin, as well as Rosa Luxemburg and John Ford. This cut-and-paste approach would have earned him the tag "postmodernist" - except he took his quoted thinkers more seriously than that term often implies.

To the British, ideas are like names - you can get away with dropping them, but only very lightly. Light, though, was not Kitaj's style - and that was to be his undoing with London critics. A retrospective at the Tate in 1994 came with portentous titles and captions, and it earned him more catcalls than most artists face over an entire lifetime. "It is a sybaritic sphinx without a riddle," said this newspaper, in a review that reads like a series of opportune yet precise kicks.

He left London, sealing his reputation as both bombastic and thin-skinned. There was also wry humour, as in the series of paintings done as he turned 60. They did not have titles so much as whinges: Bad Back, Bad Eyes, Bad Foot, Bad Thoughts. With Kitaj's career finally over, critics have another chance to judge all his facets.